One reader decision per article
Each article begins with a defined search intent, water source, treatment problem, installation type, and reader decision. Supporting keywords may add context but cannot change the page into a different article type. Listicles, exact-product reviews, A-vs-B comparisons, and informational resources use separate research and validation paths.
Evidence hierarchy
We prefer current certification-body listings, government and water-utility guidance, manufacturer manuals and performance data sheets, exact product records, current retailer availability, and model-linked buyer feedback. Marketplace bullets can support product discovery, but they do not override a certification record, manual, or exact model specification.
Certification and reduction claims
We preserve the difference between a certified product, a product tested to a standard, and a product made with certified components. A standard number is reported only when the exact model evidence supports it. A certification to one standard or reduction claim is never expanded into unrelated contaminant claims.
Editorial independence
Affiliate eligibility does not decide inclusion, rank, award, or verdict. We do not invent prices, specifications, certifications, removal percentages, testing, ownership experience, quotations, or professional credentials. Manufacturer statements and buyer reports are attributed as such.
Updates and corrections
Published URLs and original publication dates remain stable. Material updates receive a visible updated date. Confirmed errors are corrected as promptly as practical, and meaningful changes may be recorded in the article update note.